This project is an investigation of prostaglandin production by synovial tissue in rheumatoid arthritis. The regulation of biosynthesis of PGs will be investigated utilizing chromatographic and radioimmunoassay techniques. The incorporation of 1-14C-arachidonic acid into tissues in culture, and the products formed from the radioactive arachidonate in tissue culture will be characterized. The effects of non-steroidal anti-inflammatory drugs, and glucocorticoids on the metabolism of lipids containing arachidonic acid, and on arachidonic acid metabolism will be determined, in order to clarify the mechanisms of the inhibition of prostaglandin synthesis by these drugs in human synovial tissues. The stimulating effects of anti-microtubule agents and by a factor produced by human lymphocytes will be also studied. Finally, the concentrations of prostaglandins will be measured by radioimmunoassay in synovial fluids from patients with rheumatic diseases before and after treatment with anti-inflammatory drugs. BIBLIOGRAPHIC REFERENCES: Dayer, J-M., Robinson, D.R., and Krane, S.M.: Actions of anti-inflammatory drugs on synovium. In Rheumatoid Arthritis, J.L. Gordon and B.L. Hazleman, editors. Elsevier, 1977, p. 117-127. Dayer, J-M., Robinson, D.R., and Krane, S.M.: Prostaglandin production by rheumatoid synovial cells. Stimulation by a Human Lymphocyte factor. J. Exp. Med., 1977, in press.